The electric heating capacitor is used to compensate the reactive power of the induction melting furnace. The intermediate frequency electric furnace is in a high-voltage and high-current working state, and the reactive power electric heating capacitor needs to be water-cooled, and should be carefully maintained to ensure normal working conditions. The main reasons for the damage of capacitors in the maintenance of intermediate frequency furnaces are as follows:
1. The intermediate frequency electric furnace voltage is too high:
1.1 Thickness of the lining:
As a result, the load becomes higher, the power becomes smaller, and the capacitor voltage fluctuation increases.
1.2 Induction melting furnace starts too fast:
In the short time after tapping, there is no molten steel in the furnace, short-circuit discharge between the charge, causing the frequency current to flash, the drift of the load resonance point is large, and it is easy to cause the short-term inverter angle to be too large, the inverter voltage Instant rise
1.3 The charge is too bad:
During a period of time after the start of the furnace, the current and frequency are very low, and the energy of the DC reactance continuously charges the capacitor. If the load becomes lighter, the low-frequency oscillation of the capacitor increases, which tends to cause the capacitor to over-voltage in one direction.
2. Medium frequency electric furnace overheating:
2.1 The cooling water is unqualified:
The scale will cause insufficient heat dissipation, the temperature difference of the capacitor core is large, and the center withstand voltage is lowered. Insufficient water flow will cause the overall temperature rise of the capacitor to be high. Too strong corrosiveness will cause local leakage of the water-cooled coil, and the cooling water will mix with the insulating oil, resulting in greatly reduced insulation capacity.
2.2 Conductive pile head loose:
Due to the large current, the electric heating capacitor leads to more pile heads. Due to the alternating hot state of the work and the cold state of the steel discharge, it is easy to cause the pile head to loosen. The tightening screws need to be checked regularly.
2.3 The ambient temperature is too high:
The environment is poorly ventilated, and the ambient temperature is too high. Because the water-cooled coil is close to the capacitor casing, the casing absorbs heat seriously.
3. The intermediate frequency electric furnace current is too large:
3.1 Super frequency: The current of the capacitor is proportional to the frequency. The capacitor is usually damaged when it is full of molten steel. Because the frequency is the highest when the furnace is full, the current is the largest.
3.2 Capacitor short circuit: A short circuit of a capacitor will cause short-circuit discharge of the surrounding capacitor, resulting in an instantaneous large current.
